@article{DCG_1988__3_1-2_131055,
     author = {B. Mohar},
     title = {Branched {Coverings.}},
     journal = {Discrete & computational geometry},
     pages = {339--348},
     publisher = {mathdoc},
     volume = {3},
     number = {1-2},
     year = {1988},
     zbl = {0644.57001},
     url = {http://geodesic.mathdoc.fr/item/DCG_1988__3_1-2_131055/}
}